Field of the Invention
The present invention relates to a resin composition having an interpenetrating polymer network structure including an aliphatic polycarbonate obtained by copolymerizing carbon dioxide with at least one epoxide compound.
Description of the Related Art
Recently, as a method of decreasing the generation of carbon dioxide as a countermeasure on global warming, industrialization of an aliphatic polycarbonate has been developed. The aliphatic polycarbonate is a soft rubber phase plastic and has good processing properties. The decomposing properties of the aliphatic polycarbonate may be easily controlled, and thus, is widely studied as a biodegradable polymer. However, the aliphatic polycarbonate has low glass transition temperature (Tg) and is easily decomposed at about 200° C., and thus has weak heat-resistance. As for mechanical properties of the aliphatic polycarbonate, the elasticity is small, and a thin film product thereof is fragile. Thus, the application of the aliphatic polycarbonate in various fields is restricted. Accordingly, techniques on heightening the glass transition temperature or the heat-resistance, or improving the mechanical strength are required. For example, U.S. Pat. No. 4,946,884 discloses a resin composition in which polypropylene carbonate and polymethylmethacrylate (PMMA) are molten and mixed, or a binder for mold processing ceramics or metal powder is included. U.S. Pat. No. 4,912,149 discloses on improving mechanical properties by melting and mixing polyvinyl chloride acetate. However, only by blending different resins according to the disclosures, the improvement of the mechanical properties is limited. Thus, the structural improvement is necessary.
Interpenetrating polymer network (IPN) is a multicomponent-based polymer in which at least one component has a network structure, and at least one component is polymerized or networked in the presence of other components to generate interpenetration between polymer chains. Due to the network structure, the degree of the polymer chains is large. Thus, frequently generated phase separation in a polymer blend may be restrained, and dual phase continuity in which two phases make a continuous phase may be obtained. Thus, improvements on various physical properties may be expected. Accordingly, researches on applying an IPN structure is necessary in order to overcome the limitation of the physical properties of the polyalkylene carbonate resin and to enlarge an application range thereof.